Field of the Invention
Multi-ply, bonded cookware having a central area of the cooking surface that has a higher level of thermal conductivity than the more distal area of the cooking surface as well as the sidewalls of the cookware. A method for making the cookware using solid state bonding is also disclosed.
Description of Related Art
Multi-ply bonded cookware is known in the art as shown in a number of patents, such as, for example: U.S. Pat. Nos. 4,246,045 and 4,167,606 to Ulam; and U.S. Pat. Nos. 8,133,596 and 6,267,830 to Groll. These patents demonstrate that the manufacture of multi-layer bonded cookware comprising stainless steel outer layers bonded to central layer(s) of a higher conductivity aluminum and/or copper is well known in the art. The bonding between layers of these different materials is commonly achieved by conventional roll-bonding techniques using strips of aluminum and/or copper, roll-bonded to outer strips of stainless steel. It is known that roll-bonding between copper, aluminum, and stainless steel layers is conventional in the art of making composite cookware.
A solid state bonding technique using high pressure and heat to make a plurality of composite blanks of for example, stainless steel—aluminum—stainless steel in the manufacture cookware, is disclosed in our co-pending U.S. patent application Ser. No. 14/215,287.